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-   -   Increasing reliability of C7 Z51 for HPDE (https://www.corvetteforum.com/forums/c7-tech-performance/4037298-increasing-reliability-of-c7-z51-for-hpde.html)

quick04Z06 09-01-2017 02:31 PM

Increasing reliability of C7 Z51 for HPDE
 
If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.

burunet 09-01-2017 07:04 PM


Originally Posted by quick04Z06 (Post 1595486130)
If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.

AFM actuators will melt the first time you will go to the track. Nothing to worry about, it happened to me during the second 20 minute session. CEL will come on.

Other than that have fun and enjoy, it is a fun track car.:rock::rock::rock:

four0nefive 09-02-2017 12:19 AM


Originally Posted by burunet (Post 1595487660)
AFM actuators will melt the first time you will go to the track. Nothing to worry about, it happened to me during the second 20 minute session. CEL will come on.

Now that I think about it, replacing the mufflers with Z06 mufflers wouldn't be a bad idea since it doesn't have afm valves.

X25 09-02-2017 06:05 AM


Originally Posted by four0nefive (Post 1595489462)
Now that I think about it, replacing the mufflers with Z06 mufflers wouldn't be a bad idea since it doesn't have afm valves.

You'll have to connect 'something' to the plugs of those actuators, or the CEL will still come up. I ended up just cutting the actuator part of the exhaust, and left it dangling:
https://www.corvetteforum.com/forums...k-driving.html

Many seem to have purchased the simulator that's being sold by a vendor.

Z51RKT 09-04-2017 11:49 AM

You might want to get your wheels cambered as the manual suggests. I did not do that for my last HPDE and got some ugly tire wear on one side - I guess this counts as "melting".
https://cimg3.ibsrv.net/gimg/www.cor...fa9a4e1b78.jpg

dfettero 09-05-2017 09:20 AM

Track Prep reliability
 
Mobil1 15W50, Mutol RBF 600 or equivalent high temp brake fluid, adjust tire pressue expect 6-8psi increase. After 24 hr track time change rear diff fluid. Stock brakes OK for your first few times out but then go to a track pad.


Originally Posted by quick04Z06 (Post 1595486130)
If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.


quick04Z06 09-25-2017 04:05 PM


Originally Posted by X25 (Post 1595489867)
You'll have to connect 'something' to the plugs of those actuators, or the CEL will still come up. I ended up just cutting the actuator part of the exhaust, and left it dangling:
https://www.corvetteforum.com/forums...k-driving.html

Many seem to have purchased the simulator that's being sold by a vendor.

My car is a 2015. Does that simulator work well for 2015 M7 cars as far as you know? Also, can you just exhaust wrap the 6 inches of the exhaust on either side of the AFM module and provide sufficient protection from heat?

X25 09-25-2017 04:17 PM


Originally Posted by quick04Z06 (Post 1595639525)
My car is a 2015. Does that simulator work well for 2015 M7 cars as far as you know?

On a separate thread, Edgyvette stated they no longer carry those simulators. You might need to ask around.

rb185afm 09-26-2017 01:19 PM

Best thing you can do is leave the engine and tune bone stock.

dp201 06-23-2019 11:52 PM

I'm currently on my fourth set of AFM valves for my 18 GS A8. My buddy with a 17 GS is on his fifth set. I lost an entire two day event at WGI sitting in a Chevy dealer the first time it happened since I didn't realize what it was causing CEL and major noise (dealer couldn't figure it out at that point either). The down time for having the car in the shop has also been significant. GM sent my friends mufflers and pipes to an aftermarket vendor who applied a thermal insulating coating that was supposed to fix the problem. Was not a fix, they burned out again on the first track day. We run in the advanced HPDE groups with street tires. This car is built and marketed as a track/street car and if GM performed any track testing on the car with A8, they would have encountered the problem during the first 20 minutes or so. Since this is and will continue to be a recurring problem with our cars, and with no apparent permanent fix, has anyone pursued a Lemon Law claim towards a potential buy back?? If I had any idea of this problem initially, I wouldn't have purchased the car.

X25 06-24-2019 12:19 AM

Just remove it from the exhaust stream and let it hang by the side. Mine had never caused a problem with that setup.

GoatHead 06-24-2019 09:29 AM

Proper alignment (I use DSC Street/track)
Track brake pads (I use Carbotech XP12 & XP10)
Proper brake fluid (I use Castraol SRF)
Proper engine oil (I use Mobile 0W40 ESP)
Change diff fluid after the first event, and then every 4-5 events thereafter
Change Trans fluid every 4-5 events.
Inspect wheels, tires, brake lines, rotors, brake pads, wheel hubs, belts, wire harness, oil level, and coolant level before and after each event.

P.S. If you care about the factory warranty, keep the car as stock as possible.

JMII 06-24-2019 11:49 AM


Originally Posted by dfettero (Post 1595509000)
adjust tire pressue expect 6-8psi increase

I believe you meant DEcrease... as tire pressure goes up when they get hot - so you need to let some air out at the track.


Originally Posted by GoatHead (Post 1599635771)
Proper alignment (I use DSC Street/track)

How is your inside tire wear using these settings? That's the area of my Z51 that current sees the most wear. I believe this is mostly related to toe but want to go to the dealer with some knowledge.

RapidC84B 06-24-2019 11:56 AM

Just sold my 2014 Z51 in prep for the C8, but I tracked it 4-5 weekends a year and did TT a few times. Car needs nearly nothing:

1. Castrol SRF fluid

2. Stock rotors and calipers were used until the stock rotors (the early 2-part cast rotors) finally wore out after 2 seasons. Replaced with DBA single rears and 2-part fronts.

3. Used stock brake hoses w/o issue.

4. Ended up having to pull the dust boots from the calipers after they thoroughly melted and cracked.... expected.

5. G-Loc R12/R10 F/R pads.

6. Trackday alignment (-1.5/-1.2 F/R for street tires, -3/-2.2 Hoosiers)

7. Added a Z06 grill to the bumper and Z06 quarter inlet ducts to feed the trans/diff cooler... that's it... stock coolers stock radiator; zero issues run hard in VIR summer heat. Oil temp max was 266 and coolant was 232 in May, but usually stayed in the low 220s (219-222 usually). This past May was the hottest I'd run the car at 97 ambient.

Oh... if using stock seats don't bother with a harness bar or harnesses. Use the OEM belt cinch feature and get a HNR that uses the 3-point belt... holds you every bit as good as harnesses. If you go race seat, get harnesses.

PS - I bought Edgy Vette AFM sims expecting mine to fail, but they never did.

GoatHead 06-24-2019 12:55 PM


Originally Posted by JMII (Post 1599636687)
I believe you meant DEcrease... as tire pressure goes up when they get hot - so you need to let some air out at the track.



How is your inside tire wear using these settings? That's the area of my Z51 that current sees the most wear. I believe this is mostly related to toe but want to go to the dealer with some knowledge.

After 5 events (12 total days) and 4k miles after alignment, I started seeing inside wear in the front tires. I still have 4/32 on the tires, and I am going to use them for one more event.I drive to and from the track and do some street driving on weekends.

JMII 06-24-2019 01:56 PM


Originally Posted by GoatHead (Post 1599637150)
After 5 events (12 total days) and 4k miles after alignment, I started seeing inside wear in the front tires.

Thanks - that doesn't sound too bad.

I only got 3 track days out of the stock tires, but they were old (bought my '14 Z51 used) so it wasn't fresh rubber to being with.

BrunoTheMellow 06-25-2019 12:26 PM


Originally Posted by GoatHead (Post 1599635771)
Proper alignment (I use DSC Street/track)
Track brake pads (I use Carbotech XP12 & XP10)
Proper brake fluid (I use Castraol SRF)
Proper engine oil (I use Mobile 0W40 ESP)
Change diff fluid after the first event, and then every 4-5 events thereafter
Change Trans fluid every 4-5 events.
Inspect wheels, tires, brake lines, rotors, brake pads, wheel hubs, belts, wire harness, oil level, and coolant level before and after each event.

P.S. If you care about the factory warranty, keep the car as stock as possible.

Diff and trans fluid every 4-5 events is too much. You're not getting but 2 hours of track time per event. That's changing fluid every 8-10 hours of track time. Overkill.

GoatHead 06-25-2019 01:03 PM


Originally Posted by BrunoTheMellow (Post 1599643136)
Diff and trans fluid every 4-5 events is too much. You're not getting but 2 hours of track time per event. That's changing fluid every 8-10 hours of track time. Overkill.

That was based on Richie's recommendations.
Some events are 3 days and others are 2 days. There are 4 20-min sessions per day on average. I had approximately 15 hours of track time in my last 5 events.

BrunoTheMellow 06-25-2019 02:48 PM

My supercharged z51 burned spark plug wires twice. Then I added plug boots and that was fixed... These suckers run hot. Stock headers.

BrunoTheMellow 06-25-2019 02:50 PM


Originally Posted by GoatHead (Post 1599643389)
That was based on Richie's recommendations.
Some events are 3 days and others are 2 days. There are 4 20-min sessions per day on average. I had approximately 15 hours of track time in my last 5 events.

I see. I was measuring each event as 1 day.


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